1. Field of Invention
The invention concerns a device for improving the view in a motor vehicle according to the precharacterizing portion of Patent Claim 1.
2. Related Art of the Invention
Devices of this type are known from DE 41 07 850 A1 and from DE 41 37 551 A1. Therein there is shown an emission source for illuminating the vehicle environment with infrared radiation, an infrared sensitive camera for detecting at least a portion of the illuminated vehicle environment and a display for depicting the image information detected by the camera. In addition, the infrared sensitive camera is provided with an IR-filter, which is transparent to the infrared radiation of the radiation source, while being non-transparent for the remainder of the infrared emission spectrum as well as visible light due to its high blocking effect. Thereby it is accomplished that daylight as well as normal light from headlights of oncoming vehicles is completely blocked or very strongly attenuated and the interference with or disruption of the detected image information due to this extraneous light is substantially precluded.
One IR-filter of this type is available for example from the company LINOS PHOTONICS as product RG 780. It exhibits in the infrared radiation range, that is, at a wavelength of greater than 780 nm, a degree of transmission of approximately 98%, in comparison to which in the range of the visible light it exhibits a typical degree of transmission of approximately 10−5. From DE 41 37 551 A1 it is known to use an IR-filter variable in the degree of transmission in the infrared radiation range over its surface, in comparison to which the visible light is completely attenuated.